US2405085A

US2405085A - Ammunition time fuse

Info

Publication number: US2405085A
Application number: US481989A
Authority: US
Inventors: Charles F Zappone
Original assignee: PARAGON Manufacturing Co
Current assignee: PARAGON Manufacturing Co
Priority date: 1943-04-06
Filing date: 1943-04-06
Publication date: 1946-07-30
Anticipated expiration: 1963-07-30

Description

July 30, 1946. c, ZAPPQNE 2,405fi85 AMMUNITION TIME FUSE Filed April 6, 1945 I I H5912.

w INVENTOR TTORNEY Patented July 30, 1946 AMMUNITION TIIVIE FUSE Charles F. Zappone, Greensburg, Pa., assignor to Paragon Manufacturing Company, New Derry, Pa., a corporation of Pennsylvania Application April 6, 1943, Serial No. 481,989

2 Claims. 1

This invention relates to ammunition and explosive devices and, more particularly, to time fuses for hand grenades and the like.

Ammunition fuses of the type indicated may depend upon a powder train to delay explosion of the projectile for a predetermined period. Delay means of this nature is simple and economical to manufacture in quantity and may be applied in the fuse with a minimum of skill and effort. the defects of failure to perform and untimely operation due to a variety of causes chief among which are uneven burning or non-ignition of the powder and premature extinction. Fuses for delaying explosion of hand grenades, for example,

are particularly dangerous if subject to misfires, as described, with the usual proximity of thrower and target.

An object of this invention is to insure a predetermined time delay before the fuse ignites the explosive or gas forming mixture.

Another object of the invention is to simplify the manufacture of such fuses while improving the igniting characteristics.

Another object of the invention is to accomplish the foregoing purposes without renderin it necessary to materially alter the ammunition device to which the fuse is applied.

Other objects and advantages will become apparent from the following description taken in used for many years in conjunction with the common type of hand grenade. Thus the body I0 is provided with the usual offset housing I2 containing the striker mechanism, designated generally by the referenc numeral I 4. Although not forming part of this invention, this striker mechanism I4 may comprise a coil spring I 6 supported in the housing l2 on a pin l8 and carrying a striker 20 which is held in safe position by a safety pin 22 which extends through the walls of the housing I2 and may be forcibly removed by manual effort applied to a ring 24 attached to a projecting end thereof. A lever 26 is loosely anchored at one end by an inturned portion 28 thereon engaging a flange 30 on one end of the housing l0 and extends across the housing I2 Powder trains are, however, subject to 10 into operative engagement with the striker 20 in its safe position. Upon removal of the safety pin 22 as described, the striker 20 may be maintained in its safe position by manual pressure applied to the lever 26 against the bias of the coil spring which tends to rotate the striker in counterclockwise direction. When the grenade is thrown, the loose mounting of the lever 26 permits it to become detached from the grenade under pressure of the coil spring 16 which thereupon carries the striker 20 into operating position.

Referring further to the body I 0 which is generally cylindrical in form, a threaded projection 32 is provided thereon for attachment of the usual shell 34 of the hand grenade partly shown in broken lines in Fig. 1. Depending from the threaded projection 32 is an elongated projection 36, reduced in diameter from the threaded projection 32, and having an axial opening 38 extending completely therethrough and forming a junction with an enlarged axial opening 48 in the body [0. The axial opening 38 may have a counterbored portion 39 extending a short distance from the end opposite the junction described for a purpose which will be apparent hereinafter. The wall of the enlarged opening 40 is provided with a plurality, in this instance four, of longitudinal ribs M which may be equally spaced around the periphery thereof and extend longitudinally from the open end of the body In to the junction with the axial opening 38. Any desired number of ribs may be provided without departure from the salient features of this invention as will be apparent. The four ribs 4| shown may each project into the opening 40 short of the axial opening 38 and serve to reduce the free area within enlarged opening 40 to more or less rectangular form. It will be noted, however, that the ribs 4| do not project into engagement with each other but that a passage remains between adjacent ribs and the free area for a purpose described hereinafter.

As previously indicated, the time fuse of this invention is of the powder train type and the construction and arrangement of the portions now to be described in the fuse body forms the subject matter of this invention. Accordingly, a time delay element 42 comprising a tubular portion containing a core 44 of combustible material, such as black powder, is provided for insertion in the fuse body H). The delay element 42 may conveniently be formed by cutting the desired amount from a length of prefabricated material which can be purchased in coils several feet in length on the open market. The tubular 3 portion of the delay element 42 is preferably of metal, such as brass or lead, and the powder charge forming the core 44, which is solidly packed therein, may be chosen to giv the required burning time, usually four or five seconds, as desired.

The delay element i2 is preferably a close sliding fit in the fuse body I and before assembly therein a small quantity of powder is removed from one end leaving a tubular end portion which projects into the enlarged opening 40 of the body. This tubular end may be punched or swaged in the body Hi so that a head 58 comprising a plurality, in this instance, four projections are formed thereon extending between the ribs 4! and serving to provide sealing relationship between the element and the body.

The opposite end of the delay element 42 projects from the counterbored end 39 of the body after being secured as described. Preferably, the core i l of this projecting end portion is countersunk, as at 54, to increase the surface area of the powder and thus enlarge the flame produced thereby. A detonator element 46 consisting of a tubular pcrtion of metal or other suitable material containin a core 48 of an explosive powder. such as tetryl, is mounted in the counterbor ed portion by telescopic engagement with the projecting end of the delay element. A capsule mounts the core Q8 and a space 52 is left ween the end of the delay element and the capsule when the parts are assembled. In this embodiment the capsule may contain a fulminate charge at, but it will be understood that other types of fuses may be made by substituting black powder for the fulminate and detonator charges described.

The elongated projection 36 of the body i0 is of suliicient length to extend approximately midway of the telescoped ends of the detonator element 45 and the delay element 42 when inserted and secured in the body, as described. The counterbore as accommodates the end of the detonator element d6 so that the portion of the elongated projection 36 which encloses the telescoped ends may now be crimped or swaged to form a depression 52 in the elongated projection 35 and a corresponding depression in the telescoped ends of the detonator element 46 and the delay element 42. In this manner, these elements are held rigidly in position in the elongated projection 36.

In order to retain the detonator and delay elements in assembled relation and, more importantly. to provide a seal therebetween, the telescoped ends of these members may be provided with a plurality of corrugations 55 extending circumferentially thereof and which may conveniently be formed after assembly of these elements by spinning, rolling or swaging. The corrugations 5e are preferably located at some distance from the end face of the detonator element 45 in order to provide an unbroken surface on that portion of this element which is inserted the fuse body E9, A primer 54 of any suitable type, which will explode upon percussion by the striker is mounted in the ribbed opening 45 and a sealing member 6% secured in overlying relation thereto. The completed fuse is ready for assembly in the grenade or other device of which it forms a component.

The operation of the fuse occurs upon release of the grenade in action which will permit the striker 20 to contact the rimer 64 through the sealing member 66 with sufiicient force or per- 4 cussion to explode the primer 64 and ignite the charge 44 of the delay element 42.

Owing to the seal established by the head 58 at the junction of the axial opening 38 with the enlarged opening 46 in the body I0, there is no opportunity for the explosive charge of the primer 6 3 to by-pass the delay element 42 and ignite the detonator charge prematurely. The closely packed core id of combustible material in the delay element will burn evenly at the predetermined rate and, when it is substantially consumed after four or five seconds or other predetermined period, the fulminate charge iii in capsule 50 will operate to explode the detonator material 48 and the function of the fuse is fulfilled. As is Well-known, the grenade shell 34 may contain an explosive charge which operates instantaneously upon explosion of the detonator element 46 to cause the required damage at the target. In the case of gas grenades the fulminate and detonator charges may be replaced with black powder which will ignite and cause release of gaseous medium from the grenade casing.

It will be observed that when the core 44 forming the delay charge is substantially consumed, there is no opportunity for a backfire from'the next powder in the train owing to the seal established by the corrugations 56 in the detonator element 46 and the delay element 42. Thus, the fuse assembly is sealed at the initial and finishing stages of the time delay, so that after operation of the primer 6d the combustible material of the delay charge 4 3 must be substantially consumed from the primer to the detonator before the latter can operate. As a solid charge of combustible material is utilized for the time delay element, substantially even burning will occur and the redetermined time delay is assured before the explosive mixture in the grenade is ignited.

From the foregoing "it will be apparent to those skilled in the art that the standard form of hand grenade fuse is adapted without substantial change to embody the features of this invention. The solid charge delay element can readily be produced from standard materials purchasable on the open market. Desired variations can be made in the length of the time delay by varying the type of combustible material to give the required characteristics. Other changes can be made in the arrangement and combination of parts and in the details of construction herein disclosed within the scope of the appended claims without departing from the spirit of the invention.

I claim:

l. A time fuse for a grenade casing comprising in combinatioma hollow body having the opening therein enlarged at oneend a plurality of spaced ribs projecting from the interior wall of said enlarged open end and reducing the free area thereof, a primer supported by said ribs in'said free area, a detonator element projecting from said body opposite said enlarged open end, and a time delay element in said body including a tubular portion having one end adjacent said primer and the other end connected to said detonator element, said tubular portion having a plurality of radial projections formed on said adjacent end and extending between said ribs for sealing said portion to said body. v

2. A time fuse for a grenade casing comprising in combination, a hollow body having the opening therein enlarged at one end to define a shoulder therein, a plurality of spaced ribs pro- Jecting from the interior wall of said enlarged open end to the margin of said shoulder and reducing the free area of said end to substantially equal the area of said opening, a primer supported by said ribs in said free area and spaced from said shoulder, a detonator element projecting from said body opposite said enlarged open end and being peripherally deformed into fixed relation With said body, and a time delay element in said body including a tubular portion having one end adjacent said shoulder and the other peripherally deformed into fixed relation with said detonator element, said tubular portion having a plurality of radial projections formed on said adjacent end and extending between said ribs for sealing said portion to said body.

CHARLES F. ZAPPONE.